Bathroom leak repair

Your ceiling needs to be repaired or replaced anyway, no?

It could well be that these two particular leak repairs are both best accessed through your apartment. All depends on the specifics. Based on what the super can see from outside the walls, and his or her experience with similar issues elsewhere in the building, I wouldn't hesitate to trust that the best path (at least initially). You can certainly ask him or her to explain the pipe routes and why he or she thinks access from above isn't appropriate. But I wouldn't push it beyond a 10-minute conversation to help you understand the thought process.

ok, so when there is a leak under a bathroom,the first thing is to open up the ceiling under the leak.so the second part is correct.only the ceiling repair is the responsibility of the apartment with the leak.the first part of it,it could have been that the leak was coming from your shower body.at that point it is correct to do it tr]thru your kitchen.if it was a drain problem.then it should have been addressed from downstairs.